Table 4. Percent Vaccinated more than 7 Days Prior to Illness Onset by Case Control Status and Adjusted Vaccine Effectiveness, by Age Group and Vaccine Type.
| Age (Years) | Influenza Positive Cases %Vaccinated | Influenza Negative Controls (N Vaccinated/Total) | %Adjusted Vaccine Effectiveness1 (95% Confidence Interval) |
| a. Any Pandemic Vaccine | |||
| All | 12.2 (22/1011) | 19.3 (1107/5746) | 57.9 (32.4, 73.7) |
| 0.5–9 | 2.4 (9/377) | 29.6 (531/1791) | 50.8 (−8.4, 77.7) |
| 10–49 | 1.8 (9/536) | 14.2 (312/2193) | 59.0 (14.7, 80.3) |
| ≥50 | 4.1 (4/98) | 15.0 (264/1762) | 22.3 (−134.8, 74.3) |
| b. Inactivated Pandemic Vaccine 2 | |||
| All | 1.0 (14/999) | 15.9 (875/5504) | 58.6 (26.2, 76.7) |
| 0.5–9 | 1.3 (7/373) | 23.7 (390/1647) | 15.9 (−107.7, 66.0) |
| 10–49 | 0. 2 (3/528) | 10.6 (222/2096) | 77.2 (24.8, 93.1) |
| ≥50 | 4.1 (4/98) | 14.9 (263/1761) | 22.2 (−135, 74.3) |
| c. Live Attenuated Pandemic Vaccine 3 | |||
| 2–49 | 0.9 (8/860) | 7.8 (230/2931) | 60.6 (12.3, 82.3) |
| 2–9 | 0.6 (2/330) | 14.3 (140/977) | 81.9 (13.6, 96.2) |
| 10–49 | 1.1 (6/530) | 4.6 (90/1954) | 26.4 (−91.3, 71.7) |
1
Adjusted for study community, cubic spline of age and time since 10/04/09 in days, insurance status, enrollment site, presence of high risk condition;
2
Excludes all with live attenuated vaccination prior to illness onset;
3
Excludes all with inactivated pandemic vaccination prior to illness onset and those not aged 2 to 49 years old.